Several issues affect wireless systems today. Current wireless systems (e.g., 4G, LTE, LTE-A, WLAN, Wi-Fi) operate exclusively in the packet switched domain. Today's wireless systems support only a single subscription/single credential using a single connectivity context between a user device and a connectivity management portion of a network (e.g., a single non-access stratum (NAS) context between a user equipment (UE) and a mobility management entity (MME)). In the past, 3G systems supported a single subscription/single credential that covered one connection in each of the packet switched and circuit switched domains. The 3G systems supported an ability to register for the two domains in a single procedure. According to that procedure, an uplink dedicated control channel (UL DCCH) message was used to carry registrations for the packet switched and the circuit switched domain networks. A serving general packet radio service (GPRS) support node (SGSN) in the packet switched domain would update the mobile switching center (MSC) on the circuit switched domain. In this way, 3G systems allowed for communication in two distinct domains using one subscription. Even so, within each given domain there existed only a single connectivity context. In other words, a 3G system, under one subscription, would use one credential to provide a device with one connectivity context in each of the circuit switched and packet switched domains. The concept of registering in multiple domains is not a part of today's paradigm, where systems, like long term evolution (LTE), operate only in the packet switched domain.
From a security point of view, identifying security parameters for a context of a single device in a 3G system could be relatively uncomplicated. For example, in 3G the signal radio bearer 2 (SRB2) was secured with the security keys of the latest context that was created. This made it straightforward to know which security context to apply to the SRB2. There were no provisions for multiple security contexts for a single physical device in a single domain, at least because only one security context was needed.
User equipment (UE) (e.g., client device, mobile device) can include a subscriber identity module (SIM) card that includes identification information and a key unique to that SIM card. A UE making use of a subscription to a service provided by a network operator is able to establish a radio link with the network by virtue of the identification and key information stored on the SIM card. In other words, there is presently a tight connection (e.g., a one-to-one relationship) between the use of an access link (e.g., for user plane and Radio Resource Control (RRC) or Media Access Control (MAC) signaling connections in case of cellular) and the connectivity context (e.g., Evolved Packet System (EPS) Mobility Management (EMM)—and EPS Session Management (ESM)—in case of LTE). Furthermore, when a UE connects with a network, in the example of LTE, a mobility management context (e.g., Evolved Packet System (EPS) Mobility Management (EMM)) and a session management context (e.g., EPS Session Management (ESM)) are created in a mobility management entity (MME); both contexts are associated with the radio link. There is a one-to-one association between the pair of contexts and the radio link. Accordingly, it may be said that the pair of related contexts are tightly coupled to the radio link.
Presently, specific services may be delivered and controlled by dedicated functionality in a core network (CN). At present, for example, 3GPP is considering a model where for a set of a given type of device (e.g., machine-to-machine (M2M) devices), dedicated mobility management entities (MMEs) are provisioned in the network, and the MME selection in the eNB considers the type of device in selecting the MME. In other words, if certain MMEs are dedicated for M2M traffic, then each eNB will know to connect a device to one and only one MME that is dedicated to M2M traffic in connection with M2M device attachment to a network. It is not possible today, however, to concurrently connect one physical UE to multiple MMEs, let alone multiple dedicated MMEs.
Systems of the future may need to support dedicated non-access stratum (NAS) functionality, including support of specific service-dedicated pre-5G NAS solutions. This support may be useful for forward compatibility. For example, a future 5G core network (CN) designed to support dedicated devices (e.g., M2M devices) might also be designed to provide that support over new radio access technology (RAT) and legacy RAT.
It is not possible today to enable both an ability to provide dedicated network functionality for the provisioning of multiple services to a single device using a single subscriber credential, and also to support additional distinct subscriber credentials. Today's wireless devices and systems have not been designed to enable this ability. Devices today may be trapped in a paradigm of using only one SIM card per device. Therefore, if a user needs to access a different set of radio links, for example during travel, the paradigm of today may force the user to obtain a different device, or a different SIM card for the device already owned.
What is needed are methods, devices, and/or systems to break the paradigm of having to obtain a different devices/SIM cards for access to different radio links and/or to overcome some or all of the above-mentioned drawbacks of the prior art.